You mean the ones on the Header and Footer chunk of the Insert tab?
You can press Ctrl + F9 to insert a pair of field delimiters and inside them
type Page so that you have
{ PAGE }
to get page numbers. Likewise { Numpages } for the total number of pages in
the document.

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Hope this helps.
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Doug Robbins - Word MVP
>I have Microsoft Word 2007 in which i'm trying to add page numbers to
>document pages. I double click on the header section, the header tab
>appears by the problem is that all the header and footer options are
>disabled. disallowing me to add numbers
> How can i enable them, please help